ACUTE EXPOSURE TO ALCOHOL DURING EARLY POSTNATAL LIFE CAUSES A DEFICIT IN THE TOTAL NUMBER OF CEREBELLAR PURKINJE-CELLS IN THE RAT

Alcohol taken regularly over a lengthy period of time has been claimed to cause the loss of neurons in both the adult and developing brain. However, it remains uncertain whether acute, as opposed to chronic, ex posure to alcohol at specified periods can also cause disruption in th e neuronal population of the developing brain. This question was inves tigated by exposing Wistar rat pups to 7.5 g/kg body weight of ethanol administered as a 10% solution via an intragastric cannula over an 8 hour period either on the 5th (PND5) or the 10th (PND10) postnatal day of age. Gastrostomy controls received a 5% sucrose solution substitut ed isocalorically for the ethanol. Another set of pups raised by their mothers was used as ''suckle controls.'' All surgical procedures were carried out under halothane vapour anaesthesia. After the artificial feeding regimes, all pups were returned to the lactating dams and wean ed at 21 days of age. Between 52 and 54 days of age, the rats were ana esthetised with an intraperitoneal injection with Nembutal and killed by intracardiac perfusion with 3% glutaraldehyde in 0.1 M phosphate bu ffer. The relatively unbiased stereological procedure known as the ''f ractionator'' method was used to estimate the total number of Purkinje cells in the cerebellum of each animal. The Purkinje cell nucleolus w as used as the counting unit; it was assumed that each Purkinje cell c ontained only one nucleolus. PND10 ethanol-treated rats and gastrostom y and suckle controls had between about 210,000-232,000 Purkinje cells in the cerebellum. However, the PND5 ethanol-treated rats had only ab out 137,000 Purkinje cells. Two-way analysis of variance procedures re vealed significant main effects of age at time of alcohol exposure and groups as well as a significant interaction between them. It is concl uded that the Purkinje cell population numbers can be disrupted by acu te exposure to alcohol on the 5th, but not the 10th, postnatal day of age. (C) 1995 Wiley-Liss, Inc.